US challenger American Magic has returned its racing yacht Patriot to the water just 10 days after a dramatic capsize threatened to ends its involvement in the America's Cup in New Zealand.

Patriot was slowly lowered into the water at the team's Auckland base and was expected to sail later in the day to begin systems checks - the first step to a full return to racing.

On its relaunch, Patriot had a new emblem over the area of the bow which had been holed - crossed band aids bearing the Italian, British and New Zealand flags and the message: "thankyou".

The 75-foot yacht has to pass inspection by the Cup measurement committee late on Wednesday in order to race against Italian challenger Luna Rossa in the best-of-seven race challenger series semi-finals which begin on Friday.

The winner of the series will progress to the Prada Cup final where it will meet Britian's INEOS Team UK.

The loser will be out of the regatta.

American Magic's shore team, assisted by boat builders from America's Cup-holder Team New Zealand, have been working around the clock since the capsize occurred to repair extensive damage, including a big hole at the bow.

The US yacht sustained internal and external damage and its complex electronic systems have had to be replaced.

The achievement of American Magic in repairing Patriot on such a tight deadline has amazed rival teams and sailing experts.

Patriot came close to sinking and was only saved by the swift response of the US team and rivals who rushed to its assistance.